Mosquito bites cause West Nile virus if the mosquito is infected with it.

Signs & Symptoms

Most people who get the virus will have no symptoms. About 1 in 5 persons will get mild ones (West Nile fever). Symptoms usually occur 3 to 14 days after being bitten by an infected mosquito. See Doctor for the following:

•Fever. Headache. Body aches.

•Skin rash on the trunk of the body (sometimes).

•Swollen lymph glands (sometimes).

About 1 in 150 persons get symptoms of a severe infection (West Nile encephalitis or meningitis). Get Immediate Care for the following:

•High fever. Stiff neck. Severe headache. Muscle weakness.

•Tremors. Confusion. Convulsions.

•Decreasing level of consciousness. Paralysis.

Prevention

Protect yourself from mosquito bites. Stay indoors at peak mosquito biting times (dawn, dusk, and early evening). Apply an insect repellent with DEET to clothing and exposed skin to last long enough for the times you will be outdoors. Wear long-sleeved shirts and long pants when you are outdoors.